SkyWest removed the bonus for 135 pilots, and now it is for Jet type rated pilots. Many of my friends received the bonus for flying a caravan at a part 135, but that was not the intent of the bonus.
My friend recently received the $7500 bonus for an SIC type rating in the Learjet, and he was not flying the jet when he started at SkyWest.
The wording is now:
A $7,500 bonus for pilots with current turbojet type rating is available upon completion of IOE. The $7,500 bonus is also available for qualified military pilots.